When brewing beverages, in particular when brewing beer, a differentiation is made between the fermentation process and the storage process. After fermentation, the yeast added in the fermentation process has no more activity left and the brewed liquid is substantially separated from the yeast. During the subsequent storage of the cooled down brew liquid, undesirable aromas are reduced and further clearing of the brewing liquid is performed, for example of the so-called young beer. In this phase, additional aromatic substances can be added to the brew liquid since no aromatic substances are bonded by the yeast anymore. When brewing beer, pressed hops pellets are typically introduced into a storage tank for the brew liquid, wherein the hops aromas are transported from the solid matrix of the hops pellets through diffusion and a negative concentration gradient into the brew liquid, thus into the young beer. This extraction of aromatic substances is also designated as dry hopping. This method, however, has disadvantages since resins exiting from the hops pellets quickly form deposit in the storage tank so that materials transition is degraded.
Another method to introduce aroma into the beer is suspending sacks or baskets that are filled with hops pellets in the storage tank. This method, however, becomes more and more inefficient with increasing tank size since on the one hand side, the ratio of surface to volume degrades during scale up and, on the other hand side, the path for the diffusion of the aromatic substances out of the solid matrix becomes longer and longer. Thus, this method is unsuitable for industrial applications.
It has therefore already been proposed to dissolve hops pellets in a separate container through which the brew liquid is pumped from the tank into a cycle and to transport the aromatic substances from the hops pellets into the beer. EP 2 500 408 A1 describes an arrangement and a method for introducing hops into a tank, wherein the hops is supplied from a hops storage container into a mixer which includes an inlet and an outlet for beer stored in a tank. The beer from the tank is pumped through the mixer and the supplied hops is mechanically milled in the mixer by a mixing tool. Mechanically milling the pellets provides excellent substance transmission of the hops aromas into the beer, the fine milled solids of the hops matrix, however, can only be precipitated with great difficulty in the subsequent filtration step due to the small particle sizes. This applies to sedimentation or filtration.
Other devices and methods are known in which the hops pellets are stored in a container and the container is then flowed through by the brew liquid. Thus, however, it cannot be excluded that swollen hops fragments clog the outlet or also that large hops fragments are carried out which then quickly sediment in the storage tank and lead to the low quality substance transfer as recited supra.